According to MDU Dvn,
The following trains were proposed to run in the SCT-PUU route
1.Kollam-Tambaram Daily with Upgradation as Superfast
2.Palaruvi Exp Extension to Tirunelveli via SCT,TSI
3.Kollam-Tenkasi Passenger (with 14 coaches)
4.Tuticorin-Kollam...
more... Passenger via TEN,TSI,SCT,PUU
5.Kochuveli-Velankanni Express via QLN,SCT,MDU,TJ
It seems that the trains will run by June 2018,After its inaguration.